HbA1c variability tied to poor outcomes in newly diagnosed type 2 diabetes

  • Li S & al.
  • Diabetes Care
  • 14 Nov 2019

  • curated by Sarfaroj Khan
  • UK Clinical Digest
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Takeaway

  • In patients with newly diagnosed type 2 diabetes (T2D), higher glycated haemoglobin (HbA1c) variability is associated with elevated risks for all-cause mortality, cardiovascular (CV) events and microvascular complications of diabetes independently of high HbA1c 

Why this matters

  • Findings suggest that frequent fluctuations of HbA1c may be an independent risk factor for poor prognosis in patients with T2D and more stable HbA1c control may benefit the patients in clinical practice

Study design

  • Retrospective study of 21,352 newly diagnosed diabetes patients (>40 years), who had ≥5 HbA1c measurements, using data from the electronic health record of Scottish Care Information-Diabetes Collaboration.
  • Based on HbA1c variability score (HVS) (calculated as the percentage of the number of changes in HbA1c >0.5% [5.5 mmol/mol] among all HbA1c measurements within an individual) patients were categorised into:
    • ≥0 to ≤20% group (reference),
    • >20 to ≤40% group,
    • >40 to ≤60% group,
    • >60 to ≤80% group and
    • >80% group.
  • Association between visit-to-visit HbA1c variability and cardiovascular events and microvascular complications assessed.
  • Funding: Sichuan University and the Department of Science and Technology of Sichuan Province.

 Key results

  • Overall, 62% of the patients had HVS ≤40%, and 12.5% had >60%.
  • Patients with HVS >80-100% vs those with HAV ≥0 to ≤20% had significantly increased risks for:
    • major adverse cardiovascular events (MACEs; HR, 2.38; 95% CI, 1.61-3.53; P<.001>
    • all-cause mortality (HR, 2.40; 95% CI, 1.72-3.33; P<.001>
    • atherosclerotic CV death (HR, 2.40; 95% CI, 1.13-5.11; P=.023),
    • coronary artery disease (HR, 2.63; 95% CI, 1.81-3.84; P<.001>
    • ischaemic stroke (HR, 2.04; 95% CI, 1.12-3.73; P=.020),
    • heart failure (HR, 3.23; 95% CI, 1.76-5.93; P<.001>
    • diabetic retinopathy (HR, 7.40; 95% CI, 3.84-14.27; P<.001>
    • diabetic peripheral neuropathy (HR, 3.07; 95% CI, 2.23-4.22; P<.001>
    • diabetic foot ulcer (HR, 5.24; 95% CI, 2.61-10.49; P<.001 and>
    • chronic kidney disease (HR, 3.49; 95% CI, 2.47-4.95; P<.001>

Limitations

  • Observational study design.
  • Risk of residual cofounding.